Experimental study of ultrasound retention of bubble-surrounded cells under various conditions of acoustic field and flow velocity

Abstract

We confirmed that bubble-surrounded cells (BSCs) contained in flow were retained on the walls of an artificial blood vessel by forming an acoustic field with multiple focal points using tempo-spatial division emission. In order to realize the cell delivery system, we investigated the relationship between the concentration of T-cells and brightness in the microscopic images. Next, we defined the applied acoustic intensity, derived from the sound pressure distribution of every type of acoustic field. We studied the retention performance of BSCs versus various flow velocities, number and spatial intervals of the focal points, and maximum sound pressure. From the results, the optimal acoustic field to retain the cells depends on both acoustic intensity and flow velocity, where multiple focal points with an acoustic intensity of 50-120 mW/cm2 were more effective than the single focal point with 180 mW/cm2 in the range of a flow velocity of 10-20 mm/s.

Experimental conditions for efficient retention of vascular endothelial cells on channel wall using lipid bubbles and acoustic interference

“…By forming a bubble-surrounded cell (BSC), in which the microbubbles are attached to the surface of a core cell, the dynamics of the cells contained in BSCs are controlled under ultrasound exposure. We confirmed that not only T-cells [13][14][15][16][17] or Colon-26 cells 18,19) but also vascular endothelial cells 20,21) are retained on the inner wall of a flow channel under an acoustic radiation force. These studies suggest that propelling forces acting on the cells are enhanced by the traveling wave reflected on the surface of the cells due to discontinuity in the acoustic impedance.…”

“…2; (a) single source acoustic field at amplitudes of P 1 = 300 kPa-pp, and (b) interferential acoustic field at amplitudes of P 1 = P 2 = 200 kPa-pp, when sinusoidal ultrasound was applied with a central frequency of 3 MHz and θ = 60°. The distribution of sound pressure was measured using an acoustic intensity measurement system (Onda AIMS III) by translating the hydrophone (Onda HNR-1000) [13][14][15][16][17][18][19][20][21] with the spatial pitch of 0.1 mm in degassed water, where the tip diameter of the hydrophone was 1.0 mm. The width of the nodes in the sound pressure distribution was regarded as 0.5 mm, which agreed with the theoretical value of the interval between nodes.…”

Investigation of damage in vascular endothelial cells caused by lipid bubbles under ultrasound irradiation to verify the protective effect on cells

“…Our group has previously reported on a technique of active cell control based on the formation of bubble-surrounded cells (BSCs) in which bubbles are attached to cells via appropriate ligands. [10][11][12][13] Using the BSCs under ultrasound exposure, we executed active induction in an artificial blood vessel, [14][15][16][17] active cell retention on a vessel wall, [18][19][20][21] and aggregation formation. [22][23][24][25] We expect that the technology of active cell retention has a potential application in cellular therapies, which deliver therapeutic cells to a target site through the blood vessel network.…”

A Novel Detachable, Reusable, and Versatile Acoustic Tweezer Manipulation Platform for Biochemical Analysis and Detection Systems

“…The latter is widely used because it allows for more precise manipulation of the cells. Active technology generally manipulates cells through external force fields such as the electric field [ 12 , 13 ], magnetic field [ 14 , 15 ] and acoustic field [ 16 , 17 ]. Acoustic manipulation technology has attracted extensive attention and research because of its advantages of non-contact, no damage, no marking, and easy manipulation.…”